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Bryan
Dodge Dakota
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7/29/2006
11:55:34

Subject: 97 AC Problems
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Need some direction on what to troubleshoot and how to go about doing so without breaking tha bank.

My 97 CC 3.9V6 has a cooling problem. The compressor kicks in and out like it should when the AC is on. The temp coming out of the dash is maybe -10 from ambient temp outside. When I try to add a can of R134a it acts like it doesn't want it and takes forever to empty the can. I bought a "recharge kit" that gave me a free pressure guage with a can of R134a. This measurement stays pretty consistent before and after the new can is added, around 45ish (will check again in a bit to get a definite number). I added a can of R134a with the 2oz of oil in it and the system seemed to cool better for a while but now I am back to square one.

That being said, I have access to a full set of R134a guages but have no clue what I should look for as far as pressure goes. I have the SD7H15 doc from Sanden for my U4692 compressor so I can repair a problem if I know what to look for when troubleshooting. What are typical low/high pressures for this system (given the temp) and what rpm should I test at?

Also, what is the likely hood of the exspansion valve being stuck and how do I go about checking that? And where is the expansion valve in the system? Also, how and where do I look to see if I have a clogged orifice tube?

Thanks for any help you guys can give me on this!



Mike Stager
Dodge Dakota
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8/01/2006
23:17:10

RE: 97 AC Problems
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http://acsource.net/acforum/index.php?sid=7c525c35874bf8b1f28614e878ba04d4

Absolutely the best resource you can get for AC questions. They've helped me out a lot in the past.

My system is running quite similar to yours...AC isn't ICE COLD, but it's better than nothing. Mine just conks out when I accelerate.

I'm running 50psi on the low side and 250 on the high side. I was told that I was running too high on the low side...should be 30psi ( according to the chart I got with the tester I have, I should get 55psi on the low side @ 90F ).



Chris G.
Dodge Dakota
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8/02/2006
00:27:27

RE: 97 AC Problems
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Hey...sounds to me like you may have gotten air in your system at one time or another. Air can interfere with R134A readings because it's structural makeup is different and does not have the same values as R134a. Try getting a set of manifold gauges and diagnosing the prob. Evacuate the system if you can and recharge. Also, the WORST mistake people make with A/C is to buy the so called "recharge" cans with oil already in them. There is no way to tell how much oil is in the system. Oil normally does not "go away" unless it has been drained out or flushed out. You may have too much oil now in the system.



Bob Lincoln
Dodge Dakota
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8/02/2006
08:15:20

RE: 97 AC Problems
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Why did you try to add R134a without first checking high and low pressures? What makes you think you need more refrigerant. Blindly charging a system can overcharge it, get you hurt or killed if you don't know what you're doing. A little knowledge is a dangerous thing.

Study all you can about automotive A/C before fooling around with it.

http://www.aircondition.com

At idle when it's 80-90F out, I'd expect about 250 psi high side, 30 psi low side. Roughly. There are charts that get more specific.



Bryan
Dodge Dakota
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8/02/2006
14:11:00

RE: 97 AC Problems
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I purchased the Haynes Automotive Airconditioning and Heating Tech Manual. When I originally added coolant the guages were reading on the low side of where they might read at. I believe the upper limit is 45 and it was at 35 at the time. With 10 pounds to play with I thought that I might try to add a bit to it and get it closer to the upper end of the spectrum and that might make it colder. It went to 37psi on the low side and stayed there. I have yet to check the high side since the original check (my uncle has the guages and I havent made it over there to check it again). The coolant I tried to add did have the 2oz of oil added to it. From what I have read recently I believe my next course of action is to flush the system and recharge.

If you guys can think of anything that might be checked easily while the charge is gone please say so.



zzark
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8/02/2006
16:23:20

RE: 97 AC Problems
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You could replace the accumulator and orifice tube.
Really flush the lines.
Remove the compressor and flush it, then add the correct amount of oil, probably PAG 100. But you need to check specs and be sure of the oil type and quantity.
And replace all the o-ring seals.
Pull a vacuum, see if any leaks.
Then add R134a


zzark



Chris G.
Dodge Dakota
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8/02/2006
17:52:34

RE: 97 AC Problems
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you DO NOT flush a compressor. That is NOT recommended by 99.9% of compressor manufacturers. Listen to me or seize up your compressor.



BigEd
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8/02/2006
18:19:23

RE: 97 AC Problems
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Just evacuate your system, put it on a good vacuum pump and see where it sucks down to. You need to get to about 29 in.wc. If it holds a vacuum, recharge it with the correct amount of refrigerant. You've probably lost a tade of oil, not much if you have a small leak, not enough to add oil to it. A 40 lb suction pressure gives you a 35.1 deg evap. coil temp. , that should be ok. If its below 40 for long, the coil will ice up. (30 lb = 26 deg) any moister in the system will freeze. I gotta go, I'll check back later.



roy
Dodge Dakota
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7/18/2012
16:02:10

RE: 97 AC Problems
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my ac kicks in just fine. the problem is it won't cool very good. i tried adding freon but will only take so much maybe half then it thats it no more, the presure seem to be to high.




see pron
Dodge Dakota
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12/20/2018
21:48:39

MxFeOSUxvSToogOF
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LAYvks Thanks so much for the article.Really thank you! Really Cool.



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